Marc Mariani, the Tennessee Titans’ ace return man, was carted off the field after suffering a broken left tibia and fibula in his lower left leg Thursday night.

Mariani was hurt in the first quarter of the Titans’ exhibition against the Arizona Cardinals in Nashville. His leg snapped near the calf (Note: The video contains graphic images of the injury) as he was sandwiched by two teammates at the end of a punt return.

Titans coach Mike Munchak told reporters after the game that Mariani had breaks in both bones.

"That's something in football you don't want to see, and it's hard to see that and continue on with the game," Munchak said.

Mariani, a third-year pro out of Montana, was fourth in the NFL with 490 punt return yards last season (10.7 average) and ran back one punt for a touchdown. He also averaged 23.4 yards per kickoff return.

Mariani was a Pro Bowl returner in 2010. Munchak called the injury very disappointing after how hard Mariani worked this offseason, turning himself into a receiver Tennessee quarterbacks trusted.

"We saw him being a great role for that along with the return game," Munchak said. "That's a big loss for us."